Electrolytic cell and anode assembly thereof



s. LYNN ETA. 3,062,733

ELEcTRoLYTIc CELL AND ANoDE ASSEMBLY THEREOF Nov. 6, 1962 NN 2p vm @mwN w QSE@ m, RNN7 R mlT WSN N LwwNS/.T uw; wNN/@mm wm @MW il QQNN I l Nov. 6, 1962 S. LYNN El'AL ELECTROLYTIC CELL AND ANODE ASSEMBLY THEREOF Filed June 5, 1961 2 Sheets-Sheet 2 INVENTORS. Sco/L ynn Char/es E O/oens/zaw B EAM. @W

#GENT Patented Nov. 6, 1962 3,062,733 ELECTROLYTIC CELL AND ANODE ASSEMBLY THEREOF Scott Lynn, Walnut Creek, and Charles F. Oldershaw,

Concord, Calif., assignors to The Dow Chemical Company, Midland, Mich., a corporation of Delaware Filed .lune 5, 1961, Ser. No. 114,884 12 Claims. (Cl. 204-229) This inventionsrelates to mercury-cathode electrolytic brine cells, and particularly to slot-type mercury-cathode cells.

A typical mercury-cathode electrolytic cell for mak-ing chlorine and alkali comprises a long, narrow trough with a mercury pool cathode at the bottom and graphite anodes suspended from or supported by a rubber-lined cover. The feed brine is flowed through the cell with very low turbu-lence. In operation of the cell the chlorine ions in the brine are attracted to the anode and thus discharged to form chlorine gas which is usually withdrawn through an outlet line which leads from the rubber lined cover. The cation, usually sodium, forms an amalgam with the mercury. The amalgam is removed from the cell and treated with water in a separate denuder device to form alkali, the mercury being thus regenerated for re-use.

Caustic soda made with mercury-cathode cells is of higher concentration and purity than caustic soda made with diaphragm type cells, but the cost of producing this caustic has heretofore been higher at most installations as compared to the cost of caustic made with diaphragm cells.

Several factors contribute to the high cost of producing caustic soda by means of mercury-cathode cells. One important factor is the high initial cost of mercury-cathode cells as compared with the cost of diaphragm type electrolytic cells. Another factor is that conventional mercury-cathode cells of the above-described type operate at relatively low current densities in order to avoid excessive polarization of electrodes and thus occupy considerable building space per unit of chlorine or caustic producing capacity.

Mercury-cathode cells of conventional design have also proven to be quite sensitive to impurities in the brine, thus necessitating that expensive brine treatment facilities be provided in order to remove bothersome impurities. Also, the amount of mercury required for the cathode has been large, `and since some of the mercury is lost during the operation of the cell, the mercury has added to both the initial investment and the cost of operation of such cells.

An attempt to overcome some of these difficulties has resulted in what is known as a slot-type mercury cathode cell. Canadian Patent No. 476,519 to Heller and Saunders illustrates and claims a slot-type cell. In slot-type mercury cathode electrolytic cells the mercury cathode usually comprises a thin layer or iilm of mercury which is swept through the cell at a high velocity as compared to the rate of ilow of the cathode material in a conventional cell as previously described. Also, in many slot-type cells, the chlorine is swept along the flat lower surface of the anode and is removed periodically from vents or is fed into an end box. In general, slot-type mercury cathode cells are capable of operation at considerably higher current densities than `are conventional mercury cathode cells.

However, it has been found that when the chlorine is swept along the lower surface of the anode for appreciable distances before being removed that the chlorine bubbles in the brine stream and clinging to the active surface of the anode form a substantial part of the resistance of the cell. The problem has been alleviated to some extent by placing rubber lined vent boxes between anode segments every two to four feet along the cell. Such means are expensive and result in anodes which still are longer thanv .is desirable if the amount of chlorine bubbles in the cell electrolyte lying between the anode and cathode is to be held to small amounts which permit eicient operation of the cell at high current densities.

Accordingly, a principal object of this invention is to provide an improved anode assembly for use in electrolytic cells.

Another object of this invention is to provide an improved anode assembly which is capable of ecient operation at high current densities in liquid cathode type electrolytic cells.

A further object of this invention is to provide an improved self-venting anode assembly for use lin a liquid cathode type electrolytic cell.

An additional object of this invention is to provide a liquid cathode type electrolytic cell which is capable of high production of halogen gas per unit area of anode surface, operates at high current densities at relatively low voltages and is relatively simple to construct and maintain.

In accordance with this invention there is provided a flowing cathode type electrolytic cell including a graphite anode having a number of so-called bleed slots which extend across the lower surface of the anode in a directiontransverse to the direction of ilow of liquid cathode and electrolyte. The first of the bleed slots is disposed near the input end of the cell and the remainder of the slots disposed downstream from the first slot, usually generally equally `spaced from one another. One or more bleed conduits in the anode are coupled to groups of consecutive bleed slots to remove brine and gas passing along or near to the lower or active surface of the anode. One or more separation chambers are provided in the anode body and one or more bleed conduits are coupled to each separation chamber wherein gas may be vented or coupled to a vented chamber and the brine is coupled to a bleed slot `disposed between each group of the consecutive bleed slots mentioned above to distribute the brine downstream from the point or points where it was drawn into the group of bleed slots. In practice the anode is usually made in segments, each segment having a group of bleed slots through which gas and brine -is removed from the lower surface of the anode and a brine re-entry bleed slot. Each segment also has bleed conduits and separation chambers so disposed that when the segments are operatively coupled in end to end relationship that the bleed conduit or conduits of one segment are coupled to the separation chamber of the next succeeding chamber and to the gas and brine entry bleed slots of its own segment. The separation chamber of each segment is usually coupled to the last bleed slot in the downstream direction along the segment.

The above described arrangement assures that the amount of gas in the brine along the length of the anode is held within reasonable limits since the gasied brine is, within the graphite anode, drawn olf, the gas separated from it, and the more or less gas free brine returned to the space between the anode and cathode at frequent intervals along the length of the anode.

The above and additional objects and advantages of this invention will best be understood when the following detailed description is read in connection with the accompanying drawings, in which:

FIG. 1 is a simplified side elevational and diagrammatical view of an improved electrolytic cell assembly made in accordance with this invention;

FIG. 2 is a longitudinal sectional view of the anode shown in FIG 1;

FIG. 3 is a fragmentary sectional view taken along the line 3-3 of FIG. 2;

FIG. 4 is a fragmentary sectional view taken along the line 4-4 of FIG. 2, and

FIG. 5 is a fragmentary sectional view taken along the line 55 of FIG. 2.

Referring to the drawings, and particularly to FIG. l, there is shown a flowing cathode electrolytic cell, indicated generally by the numeral 10, end box 12, amalgam level controller 14, amalgam decomposer 16, chlorine output header 18, brine input line 20, and brine output line 22.

The cell comprises a cathode base plate 24, which extends beyond the cell to also serve as the base of the end box 12, a composite anode assembly, indicated generally by the numeral 26, composed of anode segments 28, 30, 32, 34 joined together to form a unitary structure, and a separator-gasket structure 36 which maintains the anode spaced and insulated from the cathode base plate and also maintains a liquid and gas tight seal between the anode, cathode and the surrounding atmosphere. The sections 30, 32 are identical in structure, the section 34 differs from sections and 32 only by the absence of a bore corresponding to the small diameter bore 166g or 106b, described later.

In operation current is applied across the cell with positive electrode terminals 3S on the anode .26 being connected to a positive lead of a direct current potential source (not shown) and a negative terminal 48 coupled to the cathode base plate, the terminal 40 being electrically coupled to the negative lead of the previously mentioned potential source.

Mercury is pumped by means of the pump 41 and line 44 to the input end 45 of the cell 10 and then flows along and covers the top surface of the base plate, as is well known, forming the flowing cathode of the cell. Brine entering the. cell through the input line Ztl is fed into the cell, filling the space between the flowing cathode and the anode 26. The brine and flowing cathode ow into the end box 12 where the brine (and any chlorine or other gas entrapped therein) is withdrawn. The amalgam ilows out of the end box through the trap 42, through the amalgam level controller which maintains the level of the amalgam to provide the desired thickness of the flowing cathode in the cell, and into the amalgam decomposer 16. In the decomposer 16 the sodium is released from the amalgam and the mercury then is pumped again into the cell.

Referring to FIGS. 2 and 3, as well as to FIG. l, operation feed brine is fed, under pressure, into the anode segment 28 through the bore 60 and into the transversely extending bore 58. through the longitudinally extending bores 64, 66 and is then fed into the electrolyzing part of the cell through the bores 68, 70 and recess 46 at the input end of the segment and through similar bores (72 only is shown in FIG. 2) and the recess 56 at the output endof the segment 28.

Mercury is pumped through the cell, as explained previously, forming a flowing cathode. A direct current, with the anode polarized positive and the cathode negatively polarized, is applied across the cell.

As the brine flows through the cell between the anode segments and the ilowing cathode, the brine is electrolyzed and chlorine gas is released at the anode and sodium amalgamates with the flowing mercury cathode.

The chlorine gas forms in bubbles at the lower anode surface which faces the cathode. The bubbles and brine are swept along by the flow of brine until one of the slots (48, 50, 52, 54 or slots 118a, 118b, or 118C) in the anode is reached. Because of the pressure drop through the passage under the anode practically all of the bubbles and a substantial portion of the brine enter the bleed slots. The gas bubbles and brine pass from the slots upwardly through the bores 82, 84, 86 and 124a, 124b, and 124e and into the longitudinally extending bores 74,

ace

The brine ilows from the bore 58 76, 78, 74a, 76a, 78a, 74b, 76b, 78b, and 74C, 76C, and 78e in anode segments 30, 32, 34.

The bubbles and brine from each set of bores of the 74, 76, 78 series which are disposed in a single anode segment ilow downstream to the end of their anode segment and then into the respective groove 90, 92 or 94 (or in segment 34). From the grooves 90, 92 or 94 the gas bubbles and brine llow into the separation bores 102m b, c and 104a, b, c respectively (104e not shown).

Gas is removed from the anode segments 30, 32, 34 through the respective bores l10n, b, c and 112a, b, c and is fed into the chlorine output header 18 as shown in FIG. l.

Brine from the large longitudinally extending bores 102:1, b, c and 104a, b, c is returned to the brine stream between the anode and cathode of the cell through bores 128a, b, c, grooves 122er, b, c and recesses 116g, b, c respectively.

Gas bubbles and brine which rise into the longitudinally extending bores 74C, 76e, 78e` through the bores 124e` are discharged from the output end of the anode segment 34 through the groove or grooves 130 and thence are swept into the adjacent end box 12 where separation of the gas and brine occurs, or into other venting means.

As mentioned previously, it is not essential that each anode segment have gas withdrawal bores of the 110, 112 type, as the bores 106a, b and 108a, b provide communication between the large diameter longitudinally extending bores 102a, b, c and 104a, b, c respectively.

On occasion small amounts of mercury may become separated from the tlowing cathode and carried upwardly into the longtudinally extending bores 74a, b, c, 76a, b, c and 78a, b, c. The small diameter bores 126 a, b, c, which are aligned with bottom of the 74, 76, 78 series of bores and the bottom of the grooves 90, 92, 94, provide a continuous ilow path for the mercury drawn into the 74, 76, 78 series bores and let it ow out of bores 74C, 76C, and 78C at the downstream end of anode segment 34 through the groove or grooves 130.

From the above description of the operation of the anode it may be seen that the gas and brine which enter the slot 48, 50, 52, 54 in anode segment 28 pass upwardly into the bores 74, 76, 78, then into the bores 102a, 1Mb in anode segment 30 where the gas and brine separate and the de-gassed brine is passed back through the bores 128:1, groove 122:1 and slot 116a and thence back into the main brine stream between the active surface of the anode and the llowing cathode at the upstream end of anode segment 32.

Similarly brine and gas bubbles rising through the slots 118g of anode segment 30 and slots 118b of segment 32 are separated in the bores 102b, 104b and 102C, 104e respectively and the gas-depleted brine re-enters the space between the anode and cathode at the upstream end and the downstream end respectively of the anode segment 34.

Gas bubbles and brine rising through the slots 118e in anode segment 34 re-enter the brine stream through the groove or grooves 130 and are separated in the end box 12 as previously stated.

The spacing between successive slots whereby gas bubbles are removed from the main brine stream may vary from somewhat less than two inches to about 8 inches. Spacings of two inches between adjacent bleed slots have been found preferable. Also, it is preferred that the brine which rises with the gas bubbles through the bleed slots be returned to the main brine stream at intervals of eight inches to a foot and a half. In the embodiment shown in FIGS. l-S the brine is returned to the main stream at intervals of about ten inches as measured along the direction of low on the active surface of the facing anodecathode electrodes. Such an arrangement results in increased cell operating eiciency over wider spacing between brine re-entry slots. The precise spacing between brine return slots is of course a function of several factors including pressure drop along the anode and flow rate through the cell.

The width of the anode or the number of anode segments which may be joined together to form a single composite anode is not particularly limited except for routine mechanical considerations in handling the completed structure. Having discussed the cell structure and its operation broadly, reference is made to the anode assembly, shown in ydetail in FIGS. 2, 3, 4 and 5.

Referring to FIGS. 2 and 3, the anode segment 28, at the input end of the cell, is a composite block-like graphite member which contains a plurality of transversely disposed slots or grooves 48, 50, 52 54 in its lower surface and has recessed ends 46, 56 which, in effect, form additional similar grooves when the cell is assembled for operation with one end of the segment 28 abutting against the anode segment 30 and the other ends and sides abutting against the gasket separator structure 36.

The body segment 28 contains a transversely extending brine distribution bore 58 having a diameter of about one forth the thickness of the segment, or larger, and which has a vertically extending brine feed bore 60 communicating therewith and with the upper surface 62 of the segment. The bore 58 is near the end of the segment 28 which abuts against the separator-gasket 36. A pair of longitudinally extending brine distribution bores 64, 66, of smaller diameter than the diameter of the bore 58, extend from near one end of the segment 28 to near the other end thereof, communicating with the bore 58.

Passageways 68, 70 extend between the recess 46 and the bores 64, 66 at one end of the segment 28 (adjacent to the separator-gasket 36) and similar passageways (of which only the passageway 72 is seen in FIG. 2) extend between the recess 56 adjacent to the segment 30 and the longitudinally extending bores 64, 66.

Three other longitudinally extending bores 74, 76, 78, disposed below the bores 64, 66, extend from the end 80 of the segment 28 at least as yfar as the slot 48 in the lower surface of that segment. Bores 82, 84, 86 extend upwardly from the top 88 of the transverse slots 48, 50, 52, 54 into the longitudinally extending bores 74, 76, 78 respectively.

The segments 30, 32, and 34 are generally similar in structure (and `differ from the segment 28) in that no means are provided for supplying additional brine from external sources into the cell. Each of the segments 30, 32, 34 contains longitudinally extending bores 7411, b, c, 7611, b, c and 7811, b, c, corresponding in size and locations to the bores 72, 74, 76 in the segment 28.

In each of the segments 30, 32, 34 a transversely extending slot 90, 92, 94, is provided in the upstream end 96, 98, 100 respectively of each segment.

The length and elevation of the slots 90, 92, 94 is such that, when the respective segments are aligned in operative relationship, the downstream ends of the bores 74, 76, 78 in each of the segments 28, 30, 32 are aligned with and communicate `with the slots 90, 92, 94 respectively.

The transversely extending slots 90, 92, 94 at the upstream end of the segments 30, 32, 34, respectively, each communicate near the top thereof with the lower part of a pair of longitudinally extending bores 10211, b or c, 10411, b, or c, respectively, which are axially parallel with and of larger diameter than the bores 74, 76, 78 but are spaced between and above the bores 7411, b or c, 7611, b or c, and 7811, b or c within the respective anode segments 30, 32 and 34.

Each pair of the bores 10211, b or c, 10411, b or c extend from the upstream end of the segment which contains it (as measured according to the direction of uid ow between the anode and cathode) to near to the downstream end of the respective segment 30, 32 or 34. The bores 10411, 1041: of anode segments 30, 34 respectively are not seen in the drawings but are disposed in 6 the same relative position beside-the visible bores 10211, 1021` respectively as are the bores 102b, 104b in the segment 32.

Small bores 10611, b and 10811, b extend inwardly from the downstream end of the anode segments 30, 32, respectively, and communicate with each of the bores 10211, 10411 and 102b, 104b respectively near the top thereof. 8he bores 10611, b and 10811, b provide direct communication between the bores 10211, b, c and 10411, b, c when the anode segments 30, 32, 34 are joined together in operative relationship, and are a substitute for bores 11011, b and 11211, b.

Gas venting bores 11011, b or c and 11211, b, or c extend from each of the bores 10211, b or c and 10411, b or c respectively to the top surface of the respective anode segments 30, 32 or 34.

Each of the anode segments 30, 32, 34 has recessed end parts 11411, b or c and 11611, b, c corresponding to the recessed end parts 46, 56 respectively of the anode segment 28, although the recessed end part 46 is recessed further than are the recessed end parts 11411, b or c.

Each of the anode segments 30, 32, 34 has an array of slots 11811, b or c extending across the active (brine contacting) width of the respective anode segment generally perpendicularly with respect to the direction of ilow (along the longitudinal axis of the cell) of the mercury cathode. The slots 11811, b or c extend upwardly and have an undercut wall part (as at 120, for example) which is disposed below Vthe bores 7411, b, c, 7611, b, c and 7811, b, c respectively. The slots 48, 50, 52 and 54 of the segment'28 have similar undercut wall surfaces in their upper parts.

, The anode segments 30, 32 and 34 each have an enlarged groove 12211, b, or c respectively at the upper end of the recessed end parts 11611, b and c. The grooves 12211, b and c are cach approximately equal in width and height to the width 'and height of the undercut part' of the slots 11811, b and c.

An array of bores 12411, b or c extends between the upper end of the bleed slots 11811, 11811 and 118e to the longitudinally extending bores 7411, 7611, 7811; 74b, 76b, 78b; and 74e, 76e, 78e respectively. In addition, an array of small diameter bores 12611, b and c extends from the transversely extending slots 90, 92, 94 respectfully into the longitudinally extending bores 7411, 7611, 7811; 74b, 76b, 78b; and 741:, 761, 78c respectively. As may be seen in FIGS. 4 and 5, the slots 92, 94 (applies also to slot 90), bores 74, 76, 7811, b or c and bores 12611, b and c are all aligned so that the bottoms of the associated slots 90, 92 or 94, bores 12611 b or c and longitudinally extending bores 74, 76 or 7811, b or c lie substantially in the same plane.

A pair of vertically extending bores 12811, b or c extends between the downstream end of the respective large diameter gas collecting bores 10211, b, c and 10411, b, c and the respective grooves 12211, b or c. The bores 12811, for example, connect the bores 10211, 10411 to the grooves 12211; the bores 128b connect the bores 102b, 104b with the groove 122b, and the bores 128C connect the bores 102e, 1041.` to the groove 122e.

At the output end of the anode segment 34 grooved passageways are provided which extend downwardly between the output end of the longtiudinally extending bores 741:, 761: and 78c and the grove 1221:. Alternatively, instead of 3 separate grooved passageways, a single grooved pasageway which extends transversely and encompasses the bores 74C, 76e and 78e and extends downwardly to the groove 122C may be used. i

Usually the groove or grooves 130 andY ends of the bores 74C, 76e, 781` will not be above the gasket seal 46, but if they are a solid strip of graphite such as the strip 132 may be bonded in a substantially gas tight manner to the output end of the anode segment to prevent gas and fluid leakage from the output end of the anode.

It should be realized that each anode segment is a composite structure comprising a plurality of pieces of graphite bonded together in electrically conductive relationship with a suitable adhesive such as phenol formaldehyde, for example. Also, an electrolytic cell made in accordance with this invention may have more anode segments than the number contained in the cell shown in FIGS. 1-5.

The parts (134, for example) `of each anode segment which contain the active face are usually made of a higher quality of graphite than are the other parts of the anode structure. As the parts 134 are eroded during the operation of the cell the anode spacing with respect to the owing cathode may be adjusted to maintain good cell operation characteristics. When the parts 134 are excessively eroded they may be removed from the anode structure and new parts 134 bonded to the rest of the structure. Thus, though the anode structure is complex, the basic anode structure is used for the life of several of the parts 134 which are eroded away during operation of the cell.

Flowing cathode electrolytic cells made in accordance with this invention achieve high current efficiency because the gas which is liberated adjacent to the active surface of the anode is removed at frequent intervals from the brine stream and prevents excessive buildup of gas along the active surface of the anode (that is, the volume percent of chlorine gas in the brine solution is kept less than 50 percent of the total of gas and solution). Since the presence of gas bubbles adhering to the active face of the anode increases the anode-cathode resistance of the cell, it will be readily appreciated that sweeping the bubbles from the active surface of the anode and limiting the gas bubble content in the brine decreases the electrical resistance across the cell and results in higher operational eciency.

It is obvious that numerous mechanical variations in shapes of slots, conduits and separation bores may be made without departing from the scope of this invention.

Likewise, while this invention has been described particularly in connection with a flowing mercury cathode electrolytic cell, the anode structure of this invention is also applicable for use in other electrolytic cells where a buildup of gas in the cell feed and on the anode face raises the electrical resistance across the cell.

Also, cells having more than one anode assembly in accordance with this invention may be made;

What is claimed is:

l. An electrolytic cell including an anode, a cathode,

means for maintaining said anode and cathode in predetermined spaced apart relationship, said cathode having a generally planar surface disposed below and facing said anode, said anode being a block-like Vunitary multi-sectioned graphite structure composed of a combined electrolyte input and operating section and at least one sepa` rate operating section, said sections being secured together in end to end relationship in a uid tight manner, said anode having an upstream end, a downstream end, sides extending between said ends, a top and a bottom, the bottom surface of said multi-sectioned anode lying in a common plane and having an array of slots therein which are transverse to the longitudinal axis of said anode, the spacing between the slots of said array being between one inch and eight inches, each section containing at least two of said slots, the combined electrolyte input and operating section having internal passage means for injecting electrolyte into said cell between the anode and cathode through spaced apart slots in that section, each of said sections having at least one electrolyte and gas pickup bore extending from the downstream end of the section to near the upstream end thereof, at least one of the slots in the bottom of each section being coupled to said electrolyte and gas pickup bore in that section, the at least one slot in said input and operating section which is coupled to the electrolyte and gas pickup bore in that section lying between the slots through which electrolyte is injected, each operating section having an electrolyte and gas separation chamber including a lower `and upper part disposed therein, slot passage means at the upstream end of each section for coupling said electrolyte and gas pickup bore of the next upstream disposed section to said electrolyte and gas separation chamber of the next downstream section, passage means for coupling the lower part of said chamber to one of said slots in the bottom of said section which is disposed near the downstream end of the section, and passage means for withdrawing gas from the upper part of said chambers.

2. An electrolytic cell in accordance with claim l, wherein said cell is of the flowing cathode type.

3. An electrolytic cell in accordance with claim l, wherein the width or" each of said slots in the bottom of the anode is a small fraction of the distance along the anode bottom between adjacent slots.

4. An electrolytic cell in accordance with claim l, wherein said slots are disposed substantially perpendiculariy with respect to the direction of electrolyte llow along the space between said anode and cathode.

5. An electrolytic cell in accordance with claim l, wherein the bottom part of said chamber is above the top part of said electrolyte and gas pickup bore.

6. An electrolytic cell in accordance with claim l, wherein the electrolyte and gas pickup bore at the downstream end of the anode is coupled toa slot in the bottom of the anode which is at least closely adjacent to said output end.

7. An electrolytic cell in accordance with claim l, wherein the lower part of said slot in the upstream end of said operating section is aligned with the bottom of the electrolyte and gas pickup bore in that section and said slot and bore are connected by a small diameter passageway between the bottom of the respective parts.

8. An electrolytic cell in accordance with claim 1, wherein there are a plurality of operating sections.

9. An electrolytic cell in accordance with claim l, wherein said electrolyte is introduced near to each end of said electrolyte input and operating section.

l0. An electrolytic cell in accordance with claim l, wherein the spacing between adjacent slots is two inches.

l1. An electrolytic cell in accordance with claim 1, wherein brine from said chamber is returned to said space between said anode and cathode through slots spaced from six to fifteen inches apart.

12. An electrolytic cell in accordance with claim 1l, wherein said slots are spaced apart approximately ten inches along the bottom of said anode.

References Cited in the le of this patent UNITED STATES PATENTS 2,719,117 Blue et al Sept. 17, 1955 2,786,810 Brown Mar. 26, 1957 2,967,142 Oliver Jan. 3, 1961 2,974,098 Oliver Mar. 7, 1961 FOREIGN PATENTS 316,694 Great Britain Aug. 8, 1929 

1. AN ELECTROLYTIC CELL INCLUDING AN ANODE, A CATHODE, MEANS FOR MAINTAINING SAID ANODE AND CATHODE IN PREDETERMINED SPACED APART RELATIONSHIP, SAID CATHODE HAVING A GENERALLY PLANAR SURFACE DISPOSED BELOW AND FACING SAID ANODE, SAID ANODE BEING A BLOCK-LIKE UNITARY MULTI-SEC TIONED GRAPHITE STRUCTURE COMPOSED OF A COMBINED ELECTROLYTE INPUT AND OPERATING SECTION AND AT LEAST ONE SEPARATE OPERATING SECTION, SAID SECTIONS BEING SECURED TOGETHER IN END TO END RELATIONSHIP IN A FLUID TIGHT MANNER, SAID ANODE HAVING AN UPSTREAM END, A DOWNSTREAM END, SIDES EXTENDING BETWEEN SAID ENDS, A TOP AND A BOTTOM, THE BOTTOM SURFACE OF SAID MULTI-SECTIONED ANODE LYING IN A COMMON PLANE AND HAVING AN ARRAY OF SLOTS THEREIN WHICH ARE TRANSVERSE TO THE LONDITUDINAL AXIS OF SAID ANODE, THE SPACING BETWEEN THE SLOTS OF SAID ARRAY BEING BETWEEN ONE INCH AND EIGHT INCHES, EACH SECTION CONTAINING AT LEAST TWO OF SAID SLOTS, THE COMBINED ELECTROLYTE INPUT AND OPERATING SECTION HAVING INTERNAL PASSAGE MEANS FOR INJECTING ELECTROLYTE INTO SAID CELL BETWEEN THE ANODE AND CATHODE THROUGH SPACED APART SLOTS IN THAT SECTION, EACH OF SAID SECTIONS HAVING AT LEAST ONE ELECTROLYTE AND GAS PICKUP BORE EXTENDING FROM THE DOWNSTREAM END OF THE SECTION TO NEAR THE UPSTREAM END THEREOF, AT LEAST ONE OF THE SLOTS IN THE BOTTOM OF EACH SECTION BEING COUPLED TO SAID ELECTROLYTE AND GAS PICKUP BORE IN THAT SECTION, THE AT LEAST ONE SLOT IN SAID INPUT AND OPERATING SECTION WHICH IS COUPLED TO THE ELECTROLYTE AND GAS PICKUP BORE IN THAT SECTION LYING BETWEEN THE SLOTS THROUGH WHICH ELECTROLYTE IS INJECTED, EACH OPERATING SECTION HAVING AN ELECTROLYTE AND GAS SEPARATION CHAMBER INCLUDING A LOWER AND UPPER PART DISPOSED THEREIN, SLOT PASSAGE MEANS AT THE UPSTREAM END OF EACH SECTION FOR COUPLING SAID ELECTROLYTE AND GAS PICKUP BORE OF THE NEXT UPSTREAM DISPOSED SECTION TO SAID ELECTROLYTE AND GAS SEPARATION CHAMBER OF THE NEXT DOWNSTREAM SECTION, PASSAGE MEANS FOR COUPLING THE LOWER PART OF SAID CHAMBER TO ONE OF SAID SLOTS IN THE BOTTOM OF SAID SECTION WHICH IS DISPOSED NEAR THE DOWNSTREAM END OF THE SECTION, AND PASSAGE MEANS FOR WITHDRAWING GAS FROM THE UPPER PART OF SAID CHAMBERS. 